Wireless local area networks (WLANs) and broadband Internet connections have become commonplace in homes and small businesses. The network setup generally consists of a DSL or Cable modem and a wireless router, as illustrated in FIG. 1, Typical Home/Small Office Network Setup. A surge-protector power strip or uninterruptible power supply (UPS) may be included to reduce the likelihood of faults induced by line-voltage dropouts, brownouts, spikes and other phenomena.
High-speed Internet service is typically brought to the home via a modem, such as DSL (Digital Subscriber Line), DOCSIS (Data Over Cable Service Interface Specification), FTTH, PON, GPON or FiOS (fiber to the home, passive optical network, gigabit passive optical network, and Fiber Optic Service) or a wireless technology such as WiMax, EV-DO or HSDPA. These connection methods are also found in small businesses, which may employ T1 or T3 data service and an Integrated Access Device (IAD) for combined high-speed Internet access and multi-line telephone service. One DSLAM rack, CMTS or multiplexer will typically serve dozens to hundreds of customer-premise modems.
The customer-premise modem has grown in complexity and capability. The broadband modem was originally a simple, single-purpose device: a modulator/demodulator. It included only enough hardware and software to negotiate a connection with the service provider and translate a network-connection format such as ATM (asynchronous transfer mode) or PPP ((point to point protocol) to a computer-connection standard such as Ethernet or less commonly now, USB (universal serial bus). With increases in processing speed, reductions in power consumption, higher density RAM (generally synchronous dynamic random access memory or SDRAM) and ROM (read-only memory, generally nonvolatile “flash” memory), declining costs and growing production volume, features and functions have been added layer by layer to the modem.
A web server with multiple html or JavaScript web pages is frequently included in the modem to facilitate setup. FIG. 2, DSL Modem Web GUI Example shows web pages from the built-in web server of a typical DSL modem. The modem includes a gateway, router, DHCP server and PPPoE login and authentication. An internal clock/calendar synced via NTP (network time protocol) keeps perfect time, and automatic, scheduled checks for firmware updates occur via the Internet. To coordinate these disparate software tasks, a real-time operating system (RTOS) such as a small Linux kernel or Wind River VxWorks is typically employed. These additions have eclipsed the complexity the modem's original, acronymous functions of modulation and demodulation, and yet modem costs are so low that they are given away as incentives in service agreements and regarded as expendable by many service providers. Some cable modems include one or two full-function VoIP or voice-over-DOCSIS analog telephone adapters (ATAs) that provide the traditional BORSCHT analog telephony functions: battery feed, overvoltage protection, ringing, supervision, codec, hybrid & testing.
This broadband modem is attached to a router, typically a wireless router. The router combines the functions of Internet gateway, router, Ethernet switch, and wireless access point. The router's principal function is the distribution and sharing of a single broadband Internet connection, but it also permits sharing of files and hardware resources such as printers, mass storage and media servers. Linksys, the consumer/small-business products arm of Cisco, reports selling upwards of 100,000 wireless routers per month. WiFi access is now provided as a free service in many retail locations, and a modem and router is becoming standard fare in hotels, coffee shops, bars and restaurants.
The router has also grown in complexity: It typically includes a web server for configuration, setup and checking status, a DHCP server, an Ethernet switch, a router with port forwarding, port triggering, MAC filtering, remote management and other features. The router typically serves as the Internet gateway, and handles PPPoE or other login, functions that are frequently duplicated in the attached modem. These multiple software threads or tasks in routers generally run under a small RTOS, such as VxWorks or a kernel of Linux. Complex features that were once included in routers selling for upwards of $1,000 have migrated into $50 units. The wireless router and broadband modem are in some instances combined into a single unit.
Modems and routers have gained speed and have become user friendly as their hardware has grown complex and their software convoluted. Dozens of hardware and software engineers work together to design them. Huge blocks of RAM and ROM are included to support rapidly developed, inefficient code. Software QA managers and large groups of testers balance thoroughness against a relentless pressure to ship. Software bugs and unhandled exceptions are often discovered after a product has begun shipping, and are managed through web downloads. ESD or EMI can derail even the best of hardware and software, sometimes temporarily, sometimes permanently, depending on its intensity. The modems and routers comprising our networks mirror the complexity and reliability of the personal computers they serve: They become partially nonfunctional in ways that are most peculiar, or they become completely inoperative. Either way, they must be rebooted, typically by a Power-On Reset (POR), that is, removing power for 5 seconds or so, then restoring power. Most modems and routers also have a recessed reset button on the back that can accomplish this, but it must be used with care: pressing it for more than five seconds or so will reset the unit, but also restore all settings entered by the user to their factory defaults.
As home and small-office networks have grown in complexity, sophistication and number of users, providing their IT (information technology) support is no longer a minor responsibility. The home and small-office networks that served well with one or two users running email and surfing the web are now routing virtual private networking (VPN) traffic, Voice over Internet Protocol (VoIP) service, streaming media distribution and other applications. Network loading is higher than ever. Once a lone bookend on the shelf, the present-day home or small-office network may be distributed: part may be at home, another at the office, and third, fourth or fifth elements nestled in the air-conditioned racks of service and application providers. These small networks rival the features, functions and complexity of large-enterprise networks of five years ago. These networks comprised of multiple servers, clients, switches and routers have become more essential than the telephone. They are intricate and can be inscrutable. Troubleshooting and clearing a fault in a home or small-office network can be quite time consuming, and may require travel to two or three locations and multiple calls to tech-support lines.
Large, enterprise-level networks generally have hired handlers—trained, 24/7 IT-support professionals working full time to keep networks up and running. They monitor these networks closely, and will often fix a network glitch before its impact is widely felt. They have access to sophisticated administrative, monitoring and troubleshooting software and equipment. For remote reset and restoration, they have Ethernet-controlled, switched rack power distribution units (PDUs): power strips with individually switched, remote-controlled AC outlets. For remote access and remote reset/restore during a network outage, an independent, secondary connection such as dialup may be employed. Many homes and small offices have only as-needed or de facto IT support. Remote access and diagnostics are generally of little value or interest to the home/small-office user and are seldom used. Secondary remote access is impractical and uneconomical in homes and small offices, and is of no value when there is no one outside to use it.